Septic Order coming from Shower Drain

I recently removed the grate from my shower drain and cleaned out a huge clog of hair. I did this about a month ago and over time have noticed a septic order in my bathroom which I believe is coming from the drain. I use the bathroom frequently so I know that the trap isn't dried out but I don't know what could be causing this order. I'm on a septic system. I have 4 bathrooms but the only one with this problem is the upstairs master bathroom and it just started after cleaning this drain. Any ideas what could be causing this or what I can do to get rid of it. I haven't put any chemicals in the drain as of yet.